The objective of the proposed research is to evaluate the effectivenes of a parent training program designed for treatment of young aggressive antisocial boys. These boys have high risk for psychiatric problems of various kinds as adults. The intent of the investigator is to identify a group of these high risk children and to provide evaluation of parent training procedures in terms of their effects upon deviant, desirable, and compliant behaviors in boys selected as seriously deviant at age five and six years. The boys will be followed up for two and three years to determine the degree to which they have benefitted from the training of their parents in child management procedures based upon operant learning principles. In order to obtain base rate information on the relative rates of deviant and desirable behaviors in nonreferred, nondeviant children with which to compare the deviant children and determine when they have reached developmental expectations, groups of normal boys will be included in the project, and data obtained on their behavioral rates at the same points in time as for the deviant boys over three years.